Gordon said the brewery uses 2.5 gallons of water to make one gallon of beer. Most craft breweries use four to seven gallons of water for the same amount. If water companies impose mandatory restrictions, production could drop in the booming industry.

"If we were put in a position where we had to go to 20 percent restriction on the water usage, I have no idea how we would be able to cope with that,” Gordon said.

Even without mandatory restrictions in place, Gordon is feeling the effects of the drought. Changes in water can tweak the taste of beer, though the brewery can add or filter out some of the minerals to minimize the effect.

"What we notice is when the water supply gets a lot lower, the hardness of the water increases and that's absolutely been an indicator that we're running low,” Gordon said.

California has more than 460 craft breweries. All are hoping those essential ingredients will be abundant for years to come.

"We have to prioritize. Swimming pools may have to go empty, lawns may have to go empty, but we got to keep brewing beer," Gordon said with a laugh. "We're going to have a lot of angry people out there.”